I have a question. We did a electrochemical series experiment today for different metals. We recorded the potential difference (both positive and negative values)

One question i need to find out for class is to produce a galvanic series, with steel being the reference material.

can somebody point me in the right direction of where to start?

some of the results are
steel and zinc -500 (steel to ground)
steel and mag -860 (steel to ground)
steel and tin +46 (steel to ground)
zinc and copper -901 (zinc to ground)
steel and copper +185 (steel to ground)
If i am making steel reference point then do i stick it in middle like below.

copper +185
tin +46
steel 0
zinc -500
mag -860

Is this correct? is this not a electrochemistry series? how do i construct a galvanic series from this?